Last week the 9th Court of Appeals issued a 90-page decision in Center for Biological Diversity v. National Highway Transportation Safety Administration/California v. NHTSA in favor of the plaintiffs. The suit was brought against NHTSA’s corporate average fuel economy (CAFE) standards for light trucks – i.e., SUVs – issued in April 2006, in part for NHTSA claiming that the value of reduced greenhouse gases would be zero. NRDC, ED, Sierra Club, Public Citizen, and 11 states and the District of the Columbia joined as plaintiffs.

The NHTSA is tasked by the Energy Policy and Conservation Act (EPCA) to set CAFE standards. Its April 2006 ruling raised the light truck standard from 22 to 23.5 miles per gallon by 2010.

The court agreed with the states that NHTSA must take into account greenhouse gases, as required by the National Environment Protection Act (NEPA) following the Massachusetts v EPA Supreme Court decision: “There is no evidence to support NHTSA’s conclusion that the apppropriate course was not to monetize or quantify the value of carbon emissions reduction at all.”

In addition to agreeing that the agency conducted an inadequate environmental assessment under NEPA, the court found that NHTSA’s regulations violated EPCA in four key areas, including the “SUV loophole” (“failure to revise the passenger automobile/light truck classifications”):

NHTSA’s failure to monetize the value of carbon emissions in its determination of the MY 2008-2011 light truck CAFE standards, failure to set a backstop, failure to revise the passenger automobile/light truck classifications, and failure to set fuel economy standards for all vehicles in the 8,500 to 10,000 lb. GWR class, was arbitrary and capricious and contrary to the EPCA. We therefore remand to NHTSA to promulgate new standards consistent with this opinion as expeditiously as possible and for the earliest model year practicable.